Interactions between Fragments

Description

We can make fragments to communicate with one another and exchange data.

Example

The following code shows how one fragment can access the views contained within another fragment.

In the res/layout folder, add a new file and name it fragment1.xml. Populate it with the following:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout//  w w  w  .  ja  v  a  2  s .com
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#00FF00" >
<TextView
    android:id="@+id/lblFragment1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="This is fragment #1"
    android:textColor="#000000"
    android:textSize="25sp" />
</LinearLayout>

Also in the res/layout folder, add another new file and name it fragment2.xml. Populate it as follows:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout//  www  .ja  v  a 2  s  .c  o  m
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FFFE00" >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="This is fragment #2"
    android:textColor="#000000"
    android:textSize="25sp" />

<Button
    android:id="@+id/btnGetText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Get text in Fragment #1"
    android:textColor="#000000"
    android:onClick="onClick" />

</LinearLayout>

In activity_main.xml, add the following code:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:orientation="horizontal" >
//  w  w  w  .  ja  v  a  2 s  .c om
      <fragment
          android:name="com.java2s.myapplication3.app.Fragment1"
          android:id="@+id/fragment1"
          android:layout_weight="1"
          android:layout_width="0px"
          android:layout_height="match_parent" />
      <fragment
          android:name="com.java2s.myapplication3.app.Fragment2"
          android:id="@+id/fragment2"
          android:layout_weight="1"
          android:layout_width="0px"
          android:layout_height="match_parent" />

</LinearLayout>

Modify the MainActivity.java file as follows:


public class MainActivity extends Activity {
   @Override//w  ww  . j  av a2  s .c  o m
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
   }
}

Under the com.java2s.Fragments package name, add two Java class files and name them Fragment1.java and Fragment2.java

Add the following code to Fragment1.java:


import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
//from   w  ww .  j av a  2 s .  c  o m
public class Fragment1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater,
    ViewGroup container, Bundle savedInstanceState) {
        //Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment1, container, false);
    }
}

Add the following code to Fragment2.java:


import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
/* w  w w.  j a v  a 2s . c  o m*/
public class Fragment2 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater,
    ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(
            R.layout.fragment2, container, false);
    }

    @Override
    public void onStart() {
        super.onStart();
        Button btnGetText = (Button)
            getActivity().findViewById(R.id.btnGetText);
        btnGetText.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                TextView lbl = (TextView)
                    getActivity().findViewById(R.id.lblFragment1);
                Toast.makeText (getActivity(), lbl.getText(),
                    Toast.LENGTH_SHORT).show();
            }
        });
    }

}

Note

Debug the application on the Android emulator.

In the second fragment on the right, click the button. You should see the Toast class displaying the text "This is fragment #1".





















Home »
  Android »
    Android UI »




UI Basics
Action Bar
Animation
Button
Canvas
CheckBox
Clock Date Picker
Dialog
EditText
Event
Fragment
Gesture
GridView
ImageView
Layout
ListView
Map
Menu
Model
OpenGL
ProgressBar
RadioButton
Spinner
Tab
TextView
Thread
Toast
Video
View
WebView